Author: Tony Scotti

This report is an old (2000) and lengthy report from the General Accounting Office (GAO). To get the answer to the question, the GAO asked twenty-seven agencies eight questions. Although the response from the agencies is dated, most of the findings are still valid.

One of the advantages of age – and so far the only advantage I have found – is that I have been a witness to some of the events that changed the way the industry works and trains. These were “game-changing incidents”–vehicle attacks that rewrote the rules for close protection and security driving.

When a vehicle is approaching its limit of adhesion, a driver has two conflicting signals. The first signal is the steering wheel getting light, which means that it requires less effort to increase steering input (turn the steering wheel). The reason for this is that the adhesion the tire makes with the road is getting increasingly smaller – quickly.

The second signal is the vehicle load the driver feels at the back of the seat (their butt), which at the limit of adhesion is high.